DETECTS LASER PULSE EMITTED BY A BARREL-MOUNTED TRANSMITTER INITIATED BY THE FALL OF A FIREARM'S HAMMER; INDOOR/OUTDOOR USE; 5.5 INCH MAX. SENSITVE DIA; 5 INCH OUTER TARGET CIRCLE DIAMETER; 0.5 INCH INNER TARGET CIRCLE DIAMETER; 10 CIRCLES; 100 FT MAX. SHOOTING RANGE; UP TO 30 SHOTS PER SESSION; 110V/50HZ OR 220/60HZ POWER SUPPLY